Problem/Motivation
It started to happen after last security update. Whenever I save view, or delete display, it adds additional attachment as a new display. So they cannot be deleted because any other submit creates new attachment.
Drupal Version
8.6.10
Last Cron Run
Last run 40 minutes 7 seconds ago
(more information)
Run cron
Web Server
nginx/1.15.8
PHP
Version
7.1.26 (more information)
Memory limit
512M
Database
Version
5.5.5-10.1.36-MariaDB
System
MySQL, MariaDB, Percona Server, or equivalent
Proposed resolution
(SOLVED): Logout and login fixed the problem.

Comments
Comment #2
echo15 commentedComment #3
seemas commentedComment #4
sokolff commentedI'm trying to reproduce this issue, but it doesn't reproduce. Maybe this problem is related to your local environment?
Comment #5
linichalexey commentedComment #8
pameeela commentedThanks @seemas for updating to say that you resolved this! You can also close the issue next time that happens :)